[ccp4bb] Dependency of theta on n/d in Bragg's law

2013-08-20 Thread Pietro Roversi
Dear all, I am shocked by my own ignorance, and you feel free to do the same, but do you agree with me that according to Bragg's Law a diffraction maximum at an angle theta has contributions to its intensity from planes at a spacing d for order 1, planes of spacing 2*d for order n=2, etc. etc.?

Re: [ccp4bb] Dependency of theta on n/d in Bragg's law

2013-08-20 Thread Tim Gruene
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Dear Pietro, You may take a textbook into account which deals with Laue diffraction. If you search for the keyword Laue and the author Helliwell at the IUCR journals, you will get a large number of hits, indicating that this is by no means a

Re: [ccp4bb] Dependency of theta on n/d in Bragg's law

2013-08-20 Thread Dom Bellini
Dear Pietro, Ladd Palmer book does explain it, just first example that springs to mind. HTH D -Original Message- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Pietro Roversi Sent: 20 August 2013 15:37 To: ccp4bb Subject: [ccp4bb] Dependency of theta on n/d in

[ccp4bb] Postdoc Position in Structural Biology of Membrane Proteins

2013-08-20 Thread Wang, Da-Neng
Postdoc in Structural Biology of Membrane Proteins A postdoc position is available immediately at the Skirball Institute, New York University School of Medicine, to study the mechanism of membrane transporters using X-ray crystallography in combination with various biochemical and biophysical

Re: [ccp4bb] non-diffracting xtals

2013-08-20 Thread Mahesh Lingaraju
Hi Evgeny I do have a few free cysteine residues but i am not sure if this is the problem in my case, I say that because i have crystallized this protein with another ligand without any issues and if oxidation of cysteine residues is a problem, i would imagine that it would have happened in the

Re: [ccp4bb] non-diffracting xtals

2013-08-20 Thread Eugene Osipov
Wow! Unexpected advices! Thank you very much, for addon and Fab! Ed, you are right in both cases: about my name and protease. I think it is good idea to try to screen for crystallization conditions with bME. Mahesh, I know nothing about your object, as well as buffer conditions. May be you would

[ccp4bb] Why MAD didn't work but SAD works well

2013-08-20 Thread Yafang Chen
Hi All, I have three datasets of SeMet-incorporated protein at peak, infl and high wavelength respectively. SAD with peak dataset works well to solve the phase problem. However, MAD with all three datasets didn't work at all. The completeness of all three datasets are more than 99%. So I think

Re: [ccp4bb] Why MAD didn't work but SAD works well

2013-08-20 Thread George Sheldrick
Dear Yafang, If radiation damage is not a major problem, MAD should give you more phase information than SAD, i.e. better maps, especially at low resolution. If SAD works but MAD doesn't, there are several possible explanations: 1. (most likely) your datasets are inconsistently indexed. This

Re: [ccp4bb] Why MAD didn't work but SAD works well

2013-08-20 Thread Bosch, Juergen
Dear George, if #4 is correct, shouldn't he be able to get good SIRAS using the peak dataset as HA and the last collected dataset as native Jürgen .. Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry Molecular Biology Johns